Lots of apps use IMEI as a unique device identifier on Android. A practice that is discouraged by Google. Anyway, since 6.0, developers should find a different

Lots of apps use IMEI as a unique device identifier on Android. A practice that is discouraged by Google. Anyway, since 6.0, developers should find a different way to udid. One alternative is Advertising ID which doesn't require any special permissions but is resettable by the user (though not easily found in the system's settings) http://developer.android.com/google/play-services/id.html http://developer.android.com/google/play-services/id.html